[VAC] Re: LED Ambience and lighting.

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

Its the ultra super bright white LEDs that sell for $6 each. I did see
some with less output on of the pages posted here today. Like 5 candela
for $2.60 each compared to 7 candela for $6 that I've ordered for
experiments.

The LEDs I ordered from Hosfelt Electronics (www.hosfelt.com) are 10mm
diameter packages.

The cost of LEDs should be coming down, these are the very latest in
newest and brightest with less competition. As more makers work out the
formulae and begin to compete the prices should fall.

The cost of LEDs is high compared to incandescent lamps. So far NO light
source beats the cost of incandescent lamp technology for the lamp
itself (except maybe the summer time capture of a lightning bug or two).
But when the cost of energy to run that lamp is included, the
incandescent lamp is about the worlds worst light source (save a
kerosine lantern without a mantle or a fish oil candle). Even
fluorescents to directly replace incandescents run 15 to 30 times the
price of the incandescent, but last 10 to 50 times longer and use 1/3
the energy.

The cost of energy, when you are dragging a battery back and forth, is a
whole heap higher than the cost of buying it from the local power
company. It kind of looks as if the LED lamps might be as much as ten
times more efficient as fluorescent lamps (I'm getting cautious with my
numbers now as I study them more), which could mean a 90 ampere hour
battery could run them a long time between charges. For example, if I
turned on all three ceiling fixtures in my Caravel, the battery load
would be 17.28 amps (in theory at least) and the 90 ampere hour battery
would last 5.2 hours. With fluorescents it would last at least three
times as long. With LEDs maybe 250 hours, maybe more. That could mean
charging the battery with a 5 watt solar panel for $30 or 40 instead of
a 75 watt solar panel for ten times that.

A trade journal I was reading this evening mentioned Ledtronics
(www.ledtronics.com). I've looked over that page, they have a number of
LED assemblies including standard edison based lamps rated for 12 volt
operation. I didn't locate prices. I also didn't check out the
assemblies made for traffic light assemblies. The make a "warm"
incandescent colored assembly as well as a pure white that has more
output.

I must repeat, "It sure is HARD to invent a new wheel, these days."

Gerald J.